Law enforcement officials aren’t sure whether they’ve discovered the last of the pipe bombs mailed to prominent Democrats and other opponents of President Donald Trump. They’ve said the packages were staggered, and more could be somewhere in the U.S. mail system.

What’s more, an official tells The Associated Press that the man suspected of sending the bombs kept a list of elected officials and others who investigators believe were intended targets.

The disclosure of the list came as 56-year-old Cesar Sayoc made his initial court appearance in Miami federal court Monday, and after bomb squads were called to a post office in Atlanta about a suspicious mailing to CNN that was similar to the pipe bomb packages recovered last week.

The official said authorities had recovered soldering equipment, a printer, and stamps similar to those used on the package bombs after arresting Sayoc last week in Florida. Authorities believe he was putting explosives together in his van.

The official also said authorities have been scrutinizing Sayoc’s social media posts. The official wasn’t authorized to discuss the ongoing investigation and spoke on condition of anonymity to the AP.

The FBI said via its Twitter account that the recovered package in Atlanta was “similar in appearance” to the bubble-wrapped manila envelopes authorities say were sent by Sayoc to intended targets from Delaware to California, including former President Barack Obama, former Secretary of State Hillary Clinton and former Vice-President Joe Biden.

CNN President Jeff Zucker says all mail to CNN has been screened offsite since last week, when a series of package bombs began appearing around the country. Among them were two apparent mail bombs sent to CNN.

At least some listed a return address of U.S. Rep. Debbie Wasserman Schultz, former chair of the Democratic National Committee.

She represents the South Florida district where the former male stripper, pizza driver and strip club DJ lived in an old van covered with bumper stickers praising Trump, disparaging Democrats and CNN, and showing rifle crosshairs over liberals including Clinton, commentator Van Jones and filmmaker Michael Moore.

Sayoc was arrested Friday outside a South Florida auto parts store after investigators said they identified him through fingerprint and DNA evidence. He faces more than 50 years in prison if convicted on all charges. None of the bombs exploded and no one was injured.

WATCH: ‘He lives in a fantasy world’: Cesar Sayoc’s former lawyer

At Monday’s hearing, federal prosecutors said they will seek to keep Sayoc jailed until trial as a flight risk and a danger to the community. A judge set another hearing for Friday on whether to grant bail to Sayoc and to discuss when he will be sent from Miami to New York, where five federal charges were filed.

Shackled at the wrists and ankles in a tan jail jumpsuit, Sayoc became weepy at one point, but said little at the hearing.

Defence attorney Daniel Aaronson urged people not to rush to judgment.

“Right now, we know very, very, very little,” Aaronson said. “We do not know all the evidence the government has. You have to keep in mind he has not been found guilty of anything.”

The FBI said it believes the package intended for CNN headquarters in Atlanta that was discovered Monday is similar to those that Sayoc is accused of sending. Law enforcement officials have said they believe the packages were staggered and more could be discovered.

The New York Times said in a staff memo that it was notified by the FBI on Monday that one of its editors was on a list of potential targets of the mail-bomb suspect. Later that day, an envelope addressed to the editor raised concerns, but New York police determined that it was a false alarm. The editor was not identified.